Such bypass valves, in which an area of higher pressure can be separated from an area of lower pressure by means of a valve and can be connected to the latter, are known for example as divert air valves for internal combustion engines with a turbocharger. They serve to connect the pressure side to the suction side of the turbocharger, by means of which a surging of the turbocharger is prevented in particular during the transition from high load to the divert operation of the combustion engine.
Thus in DE 100 20 041 C2 a bypass valve for connecting the pressure side to the suction side of a turbocharger is described that features a valve rod embodied as the armature of a magnetic circuit and displaceable by means of a drive unit, which valve rod is connected to a valve closing part, whereby the valve head and the valve rod feature pressure equalization holes. In the state of closing and opening the bypass channel, these pressure equalization holes on the movable valve unit serve to achieve an equilibrium of forces with respect to the pneumatic pressures acting axially on the valve unit. For this purpose surfaces of application of force are arranged respectively in the inner chambers of the housing of the valve, which surfaces essentially correspond to the outer surfaces of application of force of the valve, so that an equilibrium of forces ensues by means of the same pressures acting on the same surfaces.
In spite of the arrangement of these pressure equalization openings, however, the opening times of a bypass valve of this type continue to be too long. Also, the required size of the electromagnetic actuators exceeds the theoretical size for activating a force-balanced valve.
It is therefore the object of the invention to create a bypass valve in which the opening time is further reduced in comparison with known valves, whereby at the same time the size of the actuator or the force to be used by the actuator is to be minimized.